pedit COW
CVE-2026-46331, nicknamed "pedit COW," is a Linux kernel local privilege escalation vulnerability in the traffic-control subsystem, specifically in net/sched act_pedit. The flaw is in tcf_pedit_act(), which computes the copy-on-write writable range for skb_ensure_writable() only once before iterating over edit keys, using tcfp_off_max_hint. That hint does not account for runtime header offsets introduced by typed keys, so part of the eventual write region may remain outside the privately copied area. As a result, packet-edit operations can perform an out-of-bounds write into shared backing memory, leading to page-cache corruption. The upstream fix moves skb_ensure_writable() into the per-key loop so the actual write offset is known for each edit, adds overflow checks on offset arithmetic, uses skb_cow() for negative offsets affecting headroom, and guards offset_valid() against INT_MIN.
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Impact, mitigation & remediation
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Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
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Remediation
Patch, then assume compromise.
Exploits
1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
Repository contains a standalone local Linux privilege-escalation exploit for CVE-2026-46331 plus a reusable primitive and a verification harness. Structure: (1) pedit_primitive.c/.h implement the core page-cache overwrite primitive by configuring tc/netlink state on the loopback interface and abusing net/sched act_pedit to write beyond a stale COW range into page-cache-backed data sent via sendfile; setup() prepares loopback networking, opens a local TCP listener on 127.0.0.1:4445, and calibrates the file-offset delta using /tmp/.pedit_calib. api_fd_write() exposes the primitive as bounded 4-byte-slot writes to an arbitrary file descriptor, including O_RDONLY descriptors. (2) test_cve.c is a non-privilege-escalation testcase that creates /tmp/cve_target, reopens it read-only, performs 10 overwrite attempts at varying offsets/sizes, and verifies that the page cache changed despite only holding an O_RDONLY fd. (3) packet_edit_meme.c weaponizes the primitive into unprivileged local root: it locates a setuid-root su binary, parses ELF headers to find the executable entry-point file offset, forks a child that unshares user and network namespaces, maps itself to uid/gid 0 inside the namespace, calls setup(), and writes x86_64 shellcode over the cached su entry point. The parent then execves su from the initial namespace, causing the setuid-root binary to execute the injected shellcode and spawn an interactive root /bin/sh. Ubuntu-specific logic optionally re-execs through aa-exec with profiles trinity/chrome/flatpak to bypass AppArmor userns restrictions. Overall, this is a real exploit repository, not just a detector: it provides both a generic arbitrary page-cache overwrite primitive and an operational local root exploit payload.
Affected products & vendors
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Recent activity
20 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
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Every observed campaign linking this CVE to a named adversary.
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Cross-references every affected SKU, including bundled OEM variants.
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